This proposed K08 Award includes a 5-year plan to develop this candidate into an independent investigator and to study very young children who have been severely traumatized. Gaps exist in the literature of how severe trauma affects infants and young children in regards to risk for later disorder, psychophysiological disregulation, and normal development. This proposal will develop this candidate with formal coursework, extensive mentorship, and the implementation of a study that is the first step of a programmatic series of longitudinal studies of traumatized young children. Primary mentorship will be provided by Carl Feinstein, M.D., Chairman of the candidate's department at Kennedy Krieger Institute. Secondary mentorship on specialized research aspects will be provided by a panel of four mentors. Short-term specific aims include implementing techniques for multidimensional assessment, including Autonomic Nervous System dysregulation (cardiac patterns), clinical-level disturbances (PTSD, dimensional symptoms, and memory disturbance), and parental/family variables. Long-term career aims include the longitudinal investigation of traumatized infants and young children to assess risk for clinical and developmental disturbances, which will lead to the development of protocols for prevention, early intervention and treatment. The study will examine 70 children, 20-48 months of age, who have suffered a life-threatening event and become symptomatic, and 70 controls. They will be followed longitudinally for psychiatric symptoms (with a focus on PTSD), memory functions, psychophysiological disregulation of heart period variability and vagal tone, and salient environmental variables with standardized assessments of parent-child interaction patterns and measures of family functioning. One- and 2-year follow-up assessments will be conducted.